Neogene sediments of the Greater Sabah margin

Rafika Ismail and Robert Hall

Aims

To investigate the provenance of sediments supplied to the Sabah margin, offshore NW Borneo during the Neogene to:

• Unravel the sources for the sands present in the deep water Sabah margin.
• Ascertain if any of these sediments may have been sourced directly from Palawan or via the Kudat Peninsula or other unrecognised source terrane.
• Show how the structural evolution in the Sabah margin and source area terranes influenced the transportation and distribution of the sediments offshore Sabah.

Background

Past studies on the NW Borneo area have mainly focused on understanding the tectonic history of the region. To date there have been very few studies that address sediment provenance, specifically in linking offshore Sabah with onshore data. Previous studies have shown that the mineralogy of some sands in the northern area of Sabah is strikingly different from other Miocene and older sandstones in the area. The lower Miocene sandstones from the Tajau Sandstone Member of the Kudat Formation have unusual heavy mineral assemblages compared to other sandstones from northern Borneo. These assemblages suggest a different source origin in comparison to other Borneo sandstones and have mineralogical similarities with sediments in Palawan, suggesting the latter as a potential source for the Kudat Sands or another so far unrecognised source terrane.